What a Windows 8 U-turn will mean for the PC

Windows 8 hasn't given PC sales the boost that OEMs were anticipating, and Microsoft is now rumored to be getting ready to do a U-turn on some of the core changes introduced. What effect will this have on the wider industry?
If Win8.1/Blue really does restore the Start Menu and allow users to choose "boot to Desktop" this may have many implications.

It might help a lot of companies and individuals seriously consider upgrading from pre-8 Windows versions.

It might spell doom for Metro ("modern") applets and the MS AppStore as their visibility fades..

If Win8.1 catches on Microsoft usage metrics may reveal usage patterns showing there is no reason to include RT at all anymore, so Win9 might lose RT/Metro entirely. Can you say "Office Assistant (Clippy)?" "Microsoft Bob?" "Active Desktop?" "Sidebar Gadgets?" "The Ribbon?"

Ok, the last hasn't departed yet either from Office or Win7 onward. Then again a lot of people are still running pre-Win7 as well as pre-2007 Office too. Will Ribbon controls become the next polarizing UI doodad to be thrown under the bus to improve sales?